Associated Press/Peter Sorel [Salma Hayek], top left and near left in '[Frida Kahlo],' is a highly glamorized and mustache-free version of the real Frida Khalo, shown in a self-portrait at lower left. Hollywood stays true to appearance in casting male historic figures, such as [Walter Matthau], above and top right, as [Albert Einstein], right, in 'IQ' in 1994. Above, shown in 'Raging Bull' and lower left, [Robert De Niro] gained 60 pounds to look more like the aging [Jake LaMotta]. Kirk Douglas far left bore a strong resemblance to Vincent Van Gogh as shown near left, in the film portrayal. [Jane Fonda], far left, and center in her portrayal of [Lillian Hellman] in 'Julia,' could not have been more different in appearance from her subject, left. A sultry [Jennifer Jason Leigh], top left, was cast as author [Dorothy Parker], center, in 1994's 'Mrs. Parker and the Vicious Circle.' Lower left: Leigh as she really looks.

Moviegoers who catch the new biopic 'Frida' will see the legendary Mexican artist Frida Kahlo impaled in a bus accident, bedding a string of male and female lovers, and enduring the amputation of a leg.

One thing they will not see: The dark, downy hair that sprouted from Kahlo's upper lip. The woman had a bit of a mustache, and it is visible in most of her photographs and the many self-portraits she painted.

But the movie takes the artist's famously hirsute lip to the makeup trailer for a wax job.

Heaven forbid that Hollywood offend our delicate sensibilities by showing historical women as they actually looked. Brilliant, accomplished women don't always come outfitted with glamour and great gams, but you'd never know it from watching the silver screen.

Which is why actress Salma Hayek sports Kahlo's unibrow look but not the mustache. Hayek has said in interviews that Miramax Studio asked her to tone down the 'stache.

What gives? Why do movie studios cast beautiful actresses to play women who were plain - and sometimes plain ugly - in real life?

Chalk it up to long-held industry wisdom about what sells and a Tinseltown Darwinism that weeds out anyone without perfect skin and porcelain teeth, sundry character actors notwithstanding.

'This has a lot to do with the way Hollywood perceives American culture,' says Peter Bardazzi, a film professor who heads New York University's Center for Advanced Digital Applications. 'For them, entertainment is still hot-wired into sex and violence, and a lot of industry people feel we're more comfortable going to the movies to watch attractive people.'

It is no secret that Hollywood is a dream factory. For every gritty, life-in-the-raw movie released, studios churn out dozens where even bit players look fresh from a spa makeover.

Perhaps the most jaw-dropping example is the 1977 movie 'Julia,' in which Jane Fonda played the writer Lillian Hellman. Hellman was many things, but she bore about as much resemblance to Fonda as Don Knotts.

The trend chugs merrily along.

Take the upcoming movie 'The Hours,' in which the British author Virginia Woolf is portrayed. Woolf wrote ground-breaking novels, but her face looked like it was mashed in a vise. So who plays her in the movie? Nicole Kidman, one of the loveliest actresses in film.

Granted, prosthetics enlarge Kidman's nose for the role. She is also given dark bags under her eyes to mimic Woolf's hangdog look. Still, you get the feeling that if Rocky Balboa walked up and did the whole 'Yo, Virginia, if you just took off your glasses...' schtick, a radiant Kidman would spring out like Venus from Zeus' brow.

The author and wit Dorothy Parker was built like a russet potato. Yet when 'Mrs. Parker and the Vicious Circle,' the 1994 movie about her life, hit theaters, she was played by sultry Jennifer Jason Leigh.

In 'Gorillas in the Mist,' Sigourney Weaver played primate researcher Dian Fossey. Weaver sported mussy hair, but that was about the extent of her resemblance to the rawboned, bush-scruffed Fossey.

And Diana Ross wasn't a vision of Billie Holiday's heroin- induced decay in 'Lady Sings the Blues.'

'I think Hollywood is convinced that's what works, that audiences want glamour in their actresses,' Bardazzi says. 'If they thought ugly worked, that's how they'd cast.'

Hollywood has no problem duplicating real life when casting movies about looks-challenged men.

When Paramount Studio needed an actor to play Albert Einstein in the 1994 movie 'I.Q.,' no one rang Robert Redford. Walter Matthau, with his bassett-hound face and shambling frame, got the part.

Robert De Niro gained 60 pounds to play fighter Jake LaMotta in his post-boxing slob mode.

Then again, in the alternate universe of the movies, actors old enough to collect Social Security are routinely cast in romances opposite lissome actresses young enough play their daughters.

Wheeler Winston Dixon, a film professor at the University of Nebraska, believes that Hollywood's beautification campaign cuts across gender lines, but agrees the practice is relentless.

'Hollywood thinks unattractive people on the screen won't sell the picture,' he says. 'I think we're in a period where audiences want larger-than-life figures on the screen that they can worship. It's pure escapism, just like we saw in the films of the 1930s.'

Dixon remains struck by his students' reaction when he showed them Eric Rohmer's 'The Green Ray,' a French film about a loveless woman's search for happiness. It is a beautiful film about a plain woman.

'My class just wasn't buying it at all. They were saying 'Why should we care about this woman? Who wants to look at someone who looks like her?'' Dixon says. 'I was stunned. I basically read them the riot act and told them their minds had turned to cheese.'

Kathleen Brady, a stage veteran with the Denver Center Theatre Company, sees Hollywood's casting habits as a sad fact of life.

'It's a business, so they're going to cast really attractive people for audiences,' says Brady, fresh off DCTC's production of 'The Skin of Our Teeth.' 'I don't think it does anything for our progress as human beings to think that all brilliant women are beautiful. I think it would really help us as people if we could look beyond appearances and see real women on screen.'

Brady recalls the 'E.T.' publicity campaign in 1982. 'It sounds silly, but I remember seeing those long, wet-looking fingers and thinking, 'Oh, yeah, right, everyone's going to fall in love with that,'' she says.

'But that movie moved us beyond what we think of as loving or beautiful.'

Still, putting rumps in seats drives Hollywood. And when a choice biopic role is pursued by top actresses - women who, as residents atop the studio food chain, are usually gorgeous - studios play the short odds.

One strange thing about a shorn and radiant 'Frida' is that the film was co-produced by a woman (Hayek, who lobbied hard for the role), and directed by a woman (Julie Taymor, renowned for visionary stage sets), says David Thomson, author of 'A Biographical Dictionary of Film.'

'The people behind the movie couldn't let the truth on her upper lip show, though they do give her armpit hair,' Thomson says. 'But overall, Hayek is dazzling in every shot.'

Thomson says the problem with this approach is that the ghastly bus accident Kahlo suffered as a young woman - a metal rail pierced her back and exited her vagina - brought her agony until her death.

'If you look at her photos, you can see the pain on her face,' Thomson says. 'It seems to me that the way to understand Kahlo's paintings is as a kind of imagined transcendence of her physical pain.

'But in the movie, even though there's an underlying resemblance between Hayek and Kahlo, you always feel you're watching a beautiful Hollywood actress and one of the great bodies of our time,' he says.

For the record, Hayek has stated that she shaved her upper lip a time or two to promote some fuzz. But she also says Miramax insisted on downplaying that look.

Which brings us to an intriguing question: Could Hollywood ever make a movie about Eleanor Roosevelt? The wife of FDR was one of the 20th century's great women. She lived a compelling life in compelling times.

But all considerations of inner beauty aside, she was plain to the point of homeliness. She knew this - spoke of how it pained her, shaped her, colored her life.

Could Hollywood make a biopic depicting the late first lady and humanitarian as she really looked?

``I'd like to think so," Bardazzi says. ``But that's a tough one."